Upgrading a Netgear switch can be very annoying…i’ve recently bought a second GS108Ev3 and wanted to upgrade the firmware initially but the switch stocks in bootloader mode (still web accessible on 192.168.0.239). By running the upgrade via Firefox or Chromium on Debian the firmware upload stops at ~7% with a timeout error. Same issue with tftp.

Solution#

Use a Windows Machine (Win 10) + Google Chrome Browser and run the firmware upgrade procedure via web interface on 192.168.0.239 – this will even work in case the Netgear ProSAFE Configuration utility throws a timeout error. VERY WEIRD!

Overall the (first) switch performs very well over the last few years and draws very low power – a great SOHO product with VLAN capabilities (PVID/Tagged/Untagged) but the firmware needs a makeover..

There are a serveral “tutorials” and code snippets out there but they wont work on modern systemd versions and may cause fatal errors! In case you want to start your firewall before the network interfaces will be initialized, you have to hook into the special systemd target network-pre.target. It is a passive target which is invoked before any network services has been started.

Additionally, you have to explicit set the DefaultDependencies=no option – otherwise systemd automatically adds dependency of the type After=basic.target to your service and your firewall is invoked AFTER networking has been started!

Systemd Service File#

The following service file assumes that your firewall script is located in /usr/sbin/myfirewall.sh

[Unit]
Description=MyFirewall

# Start before Network Interfaces coming up
Before=network-pre.target
Wants=network-pre.target
After=local-fs.target

# Do not start after basic.target!
DefaultDependencies=no

[Service]
ExecStart=/usr/sbin/myfirewall start
ExecStop=/usr/sbin/myfirewall stop

# Just Execute the shell script
Type=oneshot
RemainAfterExit=yes

Debugging Service Startup#

The systemd-analyze utility provides a really cool way to show the system startup. Finally you should verify that your firewall is executed before networking has started!

# dump the service startup
systemd-analyze plot > /root/systemd_startup.svg

Example#

Startup of the Firewall and Networking